Field of the Invention
The present invention relates to a method for manufacturing a liquid-ejecting head for ejecting liquid like ink as drops.
Description of the Related Art
In a liquid-ejecting head that ejects liquid as drops for forming a photograph, a document, a 3-dimensional structure and the like, liquid paths for receiving the liquid from tubes or tanks and directing it to plural ejection elements are formed. For example, in the case of a color-inkjet printing head that receives plural inks and leads those inks to corresponding ejection elements, flow paths from the ink-supply openings to the ejection elements must be prepared independently for each color of ink. It is also necessary to have hollow internal construction in which the size of liquid chambers for temporarily storing the respective inks can be maintained to a certain extent, and that bends and surely guides each of the inks to ejection elements for each color that are arranged in a highly-dense narrow area. Therefore, in recent liquid-ejecting heads, that hollow internal construction has become complicated.
Typically, from the aspect of ease of manufacturing, lightness, and anti-corrosiveness, the flow paths of a liquid-ejecting head are often formed using a resin mold. In Japanese Patent Laid-Open No. 2002-178538, a method is disclosed whereby in primary molding, plural parts for achieving the kind of complicated internal construction described above are formed by injecting resin into different locations inside the same mold, and then in secondary molding, the plural parts are connected to each other and resin is injected again in the connecting areas to combine these parts together inside the same mold. Hereafter, this kind of manufacturing method will be called ‘die slide injection molding’. By employing ‘die slide injection molding’, it is possible to manufacture molded parts having complicated internal structure with high precision and good efficiency.
However, as in recent years, when parts have complicated hollow construction as described above, there was a possibility that parts that were formed during the primary molding would become deformed due to pressure used for injecting resin during the secondary molding. Particularly, when a hollow area that was formed during the primary molding was located near the injection opening during the secondary molding, there was a possibility that resin would flow into that hollow area during the secondary molding and that the volume of that hollow area would be reduced. In a liquid-ejecting head, such hollow areas function as liquid paths that supply liquid to plural ejection elements. When the volume of a liquid path becomes less than the design value, or when the liquid path for only one particular color of ink is reduced, the effect also appears in the image, so the reliability of liquid-ejecting head also decreases.